CADmium: A local-first CAD program built for the browser

1. Surface tangency matching - perfectly matching the tangent of the connecting surface on either side of the corner.

2. Edge tangency following - you select an edge, and the fillet should be able to follow along all connected tangent edges.

3. Edge reference tracking - when you modify the model further up the feature tree the kernel needs to keep track of that edge, even if the surfaces that make it drastically change or are split.

All three are hard problems on their own, once you connect them all it becomes a great indicator of the capabilities and stability of a parametric kernel.

1) You don't want just 2D constraints, 3D is better. If you were writing in C++ I'd say just take our constraint solver (Like Dune3D did). Since you're loving Rust, I can point you to the work of Michael F Bryan who wrote one in Rust and blogged about it here: https://adventures.michaelfbryan.com/posts/constraints-part-...

I think his code is over at gitlab. I haven't looked at it in a couple years. He wrote that after I nerd-sniped him ;-)

2) For geometry kernels... I've got 3 classes of bugs I want to squash in the Solvespace kernel and then it should do booleans pretty reliably, but I haven't had the time. Ours is just under 6k LOC so you could learn a lot from it. My email is the same ID at gmail if you want to ping on this topic. Its been a while since I looked at Truck and I thought it had stagnated a bit. This is a really hard problem, which is why there are so few options out there even in the commercial world. Even triangulating a trimmed NURBS shell is tricky.

3) History/feature tree is closely related to the "topological naming problem" that FreeCAD has. Solvespace handles this by creating each entity from a set of known things. If you try to recreate (regenerate in our lingo) it will just return a handle to the existing entity rather than creating a new one. In other words, every entity "came from something" and that relationship is remembered. Where we handle topological naming it works perfectly. But not everything in solvespace is covered by this. You need to bake this in from the start, it's not something you can easily bolt on afterward.

4) where is the link to try out CADmium?

I agree.

> If you want to make a good one and you only have a small team, the framework had better do a lot of heavy lifting!

I am skeptical that general-purpose UI frameworks can be a good long-term solution for 3D CAD. At times, a nice UX will need to think about many of the following at once:

    - the parametric 3D model
    - its mesh approximation
    - its hidden-surface projection into lines and patches
    - the pixels in the frame buffer
    - UI widgets.

Maybe the frameworks will help for prototyping, but if the project grows, I expect at some point they will end up ditching frameworks for the core 3D viewport interactions, and have mostly their own code in between OpenGL (or similar) and mouse/keyboard events.

Frameworks for buttons, lists, etc. will probably be fine, but even those tend to be much more dynamic in 3D CAD than in average apps.

He missed BRL-CAD, which also does brep. The interface is clunky but the kernel seems advanced.